Cellular wireless communication networks provide nearly ubiquitous connectivity for mobile devices such as mobile phones, personal digital assistants, and wireless enabled laptop computers. To provide radio links to mobile devices, cellular network operators build and maintain a large number of cell towers or cell sites. For example, a large wireless network providing national coverage may comprise more than 50,000 cell sites. The quality of cellular communication service provided by cell sites depends on a number of different factors such as the number of subscribers in a coverage area of the cell site, the radio signal strength of the cell site, and the local environment including foliage. Because these factors change over time as seasons change and as population distributions change, it is a challenge for cellular network operators to evaluate the performance of their network and the quality of service provided to their customers.